The purpose of the Statistical and Clinical Coordinating Center (SC) is to provide statistical leadership, clinical coordination and data management services in support of a network of HIV vaccine trial sites in the US and abroad. The contractor will provide the scientific, technical and operational capabilities necessary to design and implement vaccine trials, as well as analyze the data generated by these trials conducted in the HIV Vaccine Efficacy Trials Network (HIVNET). The SC will work in close collaboration with the Domestic Master Contractor (DMC), International Master Contractor (IMC), Laboratory Contractor (LC), Repository Contractor (RC) and the NIAID. SC core activities will provide statistical and data support activities for vaccine efficacy trial preparedness, including statistical leadership in study design, statistical scientific support services, technical input to assist the DMC and IMC in selecting field sites for baseline/feasibility studies and HIV vaccine efficacy trials in the US and abroad, and analyses of data collected by baseline/feasibility studies. Non-core activities are compromised of statistical and data support activities for vaccine efficacy trials, including statistical leadership in the development of vaccine trials protocols coordination with the DMC and IMC in training of field staff, site monitoring, clinical coordination and quality assurance of data collected in Phase I/II (international) trials and Phase III trials (domestic and international), primary responsibility for all data management and data analysis aspects of Phase II HIV vaccine efficacy trials sponsored by the HIVNET in the US and abroad, and for Phase I/II studies abroad. The overall goal of the HIVNET, with the statistical leadership of the SC, is to expedite the development and testing of vaccines and other biomedical technologies which are capable of preventing the transmission of HIV or of diminishing the disease impact of an HIV infection.